Unless you've spent the past year living under an internet-free rock, you've likely noticed that butts have become a definite thing. Songs have been written in their honor. The #Beflie is perpetually trending. Padded underwear exists. And a slew of new butt-sculpting exercise routines have — of course — cropped up. The one we swear by: the surprisingly simple unilateral glute bridge march. First, lie on your back and pull your heels in towards your butt. Next, rise into a bridge by lifting your lower back off the floor, and raise your knees up one at a time, like you're marching through the air. "Keep your neck relaxed and don't tuck your chin," says trainer Franklin Henderson of Stronger and Company LLC. "Focus on keeping your hips at the same height when you're switching legs for the best results." Try for three sets of 45 to 60 seconds for a truly kick-ass session.

Gap Body shorts, Uniqlo bra, Nike sneakers.